Yes, the statement that Better Diesel FBC works in pre-emissions engines would include indirect injection diesel (IDI) engines as well. The same catalytic acceleration of the fuel combustion rate applies. The only caveat for such older engines is the mechanical condition of the cylinder and rings. As long as an engine is not burning excessive amounts of engine oil, then it is likely a good candidate for the fuel borne catalyst treatment. On the other hand, if the engine is burning oil then it is likely that the rings are not sealing and/or there is cylinder liner wear. Loss of "ring seal" from mechanical wear will prevent the additional pressure created by the FBC to translate into more force against the moving piston. Instead, the additional pressure will be lost to "blow by" in which the exhaust gases escape into the engine crank case during the power stroke. This condition can also be diagnosed by used engine oil analysis and would be indicated by high soot levels and/or fuel dilution.